This invention relates to environmental concerns about the disposal of waste materials in landfills. It relates especially to the use of selected waste materials as fuel, as an alternative to disposing of those waste materials in landfills.
Communities and industry have from time to time explored means for producing useful products from waste material. Some of those efforts have been directed toward producing solid fuel products from waste. A variety of communities have, for example, attempted to convert the non metallic portion of their municipal garbage as picked up from, e.g. residential areas, into solid fuel, for use in industrial furnaces, e.g. to generate power. But such projects have, on the whole, met with marginal success.
A companion problem is that users of solid fuels have experienced periodic increases in the cost of such fuels, whereby alternate, and more cost effective fuels, would be desirable, so long as the alternate fuels meet the necessary performance specifications.
It is an object of this invention to provide an alternate solid fuel, made from waste materials comprising cellulosic fiber and thermoplastic resin, wherein the alternate fuel preferably has a heat output similar to that of coal, and preferably is adapted to be used in admixture with coal, and handled using standard coal handling equipment.
It is another object to provide such an alternate fuel with predictable and consistent burning, and material handling properties, whereby the alternate fuel can be reliably fed to the furnace in combination with coal.
It is still another object to provide a pelletized alternate fuel, for admixing and feeding with coal, wherein the pellets are dimensioned such that the pelletized fuel is consumed in conventional coal fired furnaces during approximately the same time period as the coal admixed with it.
It is another object to provide a pelletized alternate fuel to completely replace the conventional fuel, such as natural gas, propane, oil or wood in burners which are capable of burning solid fuel in pelletized form.
It is yet another object to provide such fuel having an ash content between about 1.0% and about 7.0% by weight.
It is a further object to provide pelletized fuel comprising random arrangements, along the lengths of the pellets, of layers of cellulosic fiber elements and thermoplastic resin elements, the layers being disposed transverse to the lengths of the pellets.
It is a further object to control the density and burning characteristics of the fuel by selecting loose and light-weight fiber or sheet for at least a part of the cellulosic film component.
Another object is to provide fuel pellets made from conventional disposable diaper stock.
A further object is to provide fuel pellets made from conventional disposable hygiene pad stock.
A further object is to provide a method of making pelletized fuel with a cellulosic fiber component and a thermoplastic resin component.
Finally, it is an object to provide a method of firing a furnace using conventional coal handling equipment, including selecting appropriate pelletized fuel which is adapted for being handled in a conventional manner when admixed with coal.